Project refactor, add anthropic API support

- Split pkg/cli/cmd.go into new pkg/cmd package
- Split pkg/cli/functions.go into pkg/lmcli/tools package
- Refactor pkg/cli/openai.go to pkg/lmcli/provider/openai

Other changes:

- Made models configurable
- Slight config reorganization

go.mod

@@ -4,8 +4,8 @@ go 1.21
 
 require (
 	github.com/alecthomas/chroma/v2 v2.11.1
+	github.com/charmbracelet/lipgloss v0.10.0
 	github.com/go-yaml/yaml v2.1.0+incompatible
-	github.com/gookit/color v1.5.4
 	github.com/sashabaranov/go-openai v1.17.7
 	github.com/spf13/cobra v1.8.0
 	github.com/sqids/sqids-go v0.4.1
@@ -14,14 +14,20 @@ require (
 )
 
 require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/dlclark/regexp2 v1.10.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.18 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
 	github.com/mattn/go-sqlite3 v1.14.18 // indirect
+	github.com/muesli/reflow v0.3.0 // indirect
+	github.com/muesli/termenv v0.15.2 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/xo/terminfo v0.0.0-20210125001918-ca9a967f8778 // indirect
 	golang.org/x/sys v0.14.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 	gopkg.in/yaml.v2 v2.2.2 // indirect